GB714672A - Improvements relating to the production of mechanical power using internal combustion engine of diesel type - Google Patents

Abstract

714,672. Cycles; materials special; regulating. STANDARD OIL DEVELOPMENT CO. Oct. 31, 1950 [Nov. 22, 1949], No. 29819/49. Drawings to Specification. Classes 7(2) and 7(6) In a method of producing mechanical power using an internal combustion engine of Diesel type a mixture of air and an essentially vaporized secondary fuel which is different from the conventional primary fuel is introduced into the air intake to the engine and the secondary fuel is present in amount insufficient to burn under the conditions of temperature and pressure pertaining in the combustion chamber up to the time that the conventional primary fuel is injected and less secondary fuel than primary is admitted, the engine being otherwise operated under conventional Diesel conditions, the amount of conventional primary fuel being never less than that amount required to operate the engine at no load. The mixture may be a weak gasoline/air mixture. The power of the engine is increased without increasing the exhaust smoking or for a given power exhaust smoking is decreased. The proportion of fuel in the mixture to the total fuel should be less than 50 per cent. The advantages of employing the non-explosive mixture are most pronounced when the engine is running under conditions approaching maximum power so that preferably the secondary fuel is employed only when the engine is delivering 50 per cent and preferably 75 per cent of the maximum power. In one embodiment the Diesel fuel supply delivers a maximum flow corresponding to a power output of say 75 per cent to 90 per cent of the rated maximum output and for powers above this value the gasoline air mixture is fed into the intake. It is stated that fuels which may be liquefied but are vapours at normal temperatures and pressures may be used as the secondary fuels or fuels boiling in the kerosene range. Burning oil, ether and natural gas are mentioned. The gasoline may be supplied by a single-jet carburetter or an atomizing nozzle. When heavier fuels are used they are vaporized for example by exhaust heat or by an electric heater. The fuel supplies may be controlled by two lost motion devices by which the conventional fuel is supplied in gradually increasing quantity up to a certain amount and then kept constant while the supply of mixture by way of the carburetter is gradually brought into use. Alternatively an arrangement of staggered cams may be employed. When operating at standard load to reduce smoke density the octane number of the aspirated fuel seems to be of little significance, the observed smoke densities at 1,800 r.p.m. and full load being substantially the same with n-heptane, 710.N gasoline and iso-octane. The octane number does affect the maximum power obtainable at standard exhaust smoke density of 15 however. Test results are given in the Specification.